Graduated Driver Licensing (GDL) laws have significantly reduced the burden of teen crashes, in part by restricting newly-licensed teen drivers (i.e., probationary drivers) from engaging in high-risk driving behaviors. However, their effectiveness has been limited by challenges with: (1) teen drivers' willingness to comply with GDL restrictions and (2) law enforcement's ability to enforce these restrictions, given there is no obvious way to identify a probationary driver's vehicle. New Jersey (NJ) recently implemented the first-in-the-nation decal provision into their GDL law, requiring probationary drivers to disply highly-visible decals on their cars while driving. This innovative law is designed to facilitate enforcement of GDL restrictions and increase the likelihood that probationary drivers avoid high-risk driving behaviors, thereby reducing their crash risk. Although several other countries have long required decals, decal provisions have not yet been evaluated, in part because of a lack of adequate research methods. This study aims to evaluate the effect of NJ's decal provision on probationary drivers' compliance with four GDL restrictions (peer passengers limits, nighttime curfew, ban on use of electronic equipment, and required seat belt use) and police officers' enforcement of these restrictions. Additionally, the study will determine predictors of compliance with current NJ GDL restrictions in order to identify adolescent driver subgroups at high-risk of engagement in risky driving behaviors. To overcome methodological challenges, we will employ a novel application of the induced exposure technique, a validated method unique to traffic safety research. In particular, this study will borrow the technique's main principle, that non-responsible drivers in two-car crashes are randomly selected by responsible drivers from the population of road users and thus are a reasonably representative sample of the road user population, to make population- based pre- and post-law estimates of compliance among NJ probationary drivers. To address specific aims, we will analyze a linked database containing NJ crash and driver licensing information. Data from NJ's crash report will be used to identify the proportion of non-responsible probationary drivers in crashes who were complying with each restriction, while data on GDL-related citations will be used to estimate GDL enforcement among non-complying probationary drivers. This evaluation is critical to the future of GDL decal laws in the U.S., as several states are awaiting results as they consider implementing similar provisions. Further, this study will contribute to building the scientific evidence base for decal provisions - a controversial, but potentially important policy intervention to enhance GDL. Finally, this study will advance the field of young driver research by providing researchers with an innovative method to: (1) evaluate the effects of policy-level interventions on driving behavior;(2) estimate the extent of engagement in hard-to-capture risky behaviors (e.g., nighttime driving) among various young driver subgroups; and (3) identify high-risk subgroups of young drivers to target for future interventions. Although Graduated Driver Licensing (GDL) laws have significantly reduced the burden of teen motor vehicle crashes, their potential to have an even greater impact on public health hinges on efforts to enhance teen compliance with and police enforcement of GDL restrictions (passenger limit, curfew, seat belt use, cell phone restriction). This study will evaluate whether New Jersey's innovative effort to do so - a GDL law requiring novice teen drivers to display a decal on their vehicle's license plate to make themselves easily identifiable to police - increases teen drivers' compliance with and officers' enforcement of GDL restrictions. Results will productively inform future refinements of New Jersey's law, guide decisions of policymakers in other U.S. states considering similar laws, and provide much-needed scientific evidence as to the effectiveness of decal laws. PUBLIC HEALTH RELEVANCE: Although Graduated Driver Licensing (GDL) laws have significantly reduced the burden of teen motor vehicle crashes, their potential to have an even greater impact on public health hinges on efforts to enhance teen compliance with and police enforcement of GDL restrictions (passenger limit, curfew, seat belt use, cell phone restriction). This study will evaluate whether New Jersey's innovative effort to do so - a GDL law requiring novice teen drivers to display a decal on their vehicle's license plate to make themselves easily identifiable to police - increases teen drivers compliance with and officers enforcement of GDL restrictions. Results will productively inform future refinements of New Jersey's law, guide decisions of policymakers in other U.S. states considering similar laws, and provide much-needed scientific evidence as to the effectiveness of decal laws.